This invention relates to apparatus for the measurement of air pressures and/or flows and the like, in particular for medical testing of lung function.
Apparatus is already known (the MiniWright Peak Flowmeter, manufactured by Clement Clarke International Ltd, Harlow, Essex) for measuring the peak flow rate of exhalation, in which the subject blows into a cylindrical measurement container to move a piston in the container against the force of a spring. The displacement of the piston progressively uncovers an open slot in the side of the container along which a pointer is slid by the piston to mark the greatest displacement of the piston and thereby provide a measure of the peak flow rate in the subject's airways.
With appropriate calibration, this apparatus is able to give acceptable comparative results, but its use is limited. It is an object of the present invention to provide an improved instrument, and to provide such an instrument that can produce further data in respiratory testing.